Display modules that display an image using liquid crystals, organic Electro Luminescence (hereafter, abbreviated as “EL”) modules that emit light in response to electrical stimulation, and the like are used in the image display unit of electrical equipment such as a mobile phone. These display modules include modules having glass substrates and film modules having substrates made of resin film. FIG. 5 is a schematic perspective view of a conventional color display module using liquid crystals.
The display module is composed of a display panel 51, three flexible boards 52, 53, and 55, and a main flexible board 54 with which the flexible boards 52, 53, and 55 are connected. The display panel 51 includes a lamination of two glass or resin plates and liquid crystals sealed therebetween. Three flexible boards 52, 53, and 55 are each electrically connected with transparent electrodes that are made of an Indium Tin Oxide (ITO) film or the like and are formed on the surface of the edge portions of three sides of the display panel 51. The display panel 51 includes common and segment electrodes formed thereon. The transparent electrodes connected with those electrodes are electrically connected with a wiring pattern formed on the flexible boards 52, 53 and 55 using electrically conductive tape or paste. In addition to the wiring pattern, the flexible boards 52, 53, and 55 are provided with driver ICs 52a and 53a for driving the liquid crystals sealed in the display panel 51.
The flexible boards 52, 53, and 55 are each soldered to a wiring pattern on the main flexible board 54 with solder joints 52b, 53b, and 55b. Alternatively, these flexible boards are electrically connected with the wiring pattern on the main flexible board 54 by means of connectors or the like. On one end portion of the main flexible board 54, a connector portion 54a is formed. Further, circuit components 54b are mounted on the main flexible board 54. Here, the circuit components 54b include a circuit for exchanging signals with the flexible boards 52, 53, and 55 and a resistor and a capacitor used for exchanging signals with the circuit board included in the main body of the mobile phone.
In the color display module having the above-stated construction, pictures and characters can be displayed on the display panel 51 by electrically connecting the connector portion 54a with the circuit board included in the main body of the mobile phone and inputting signals therein.
Although not illustrated, in the case of organic EL modules as well, connector portions are provided on the edge portions of three sides of the panel, similar to the display panel 51.
However, since such a conventional display module is constructed by assembling four flexible boards (i.e., 52 through 55), the overall size of the device becomes large. Additionally, when incorporating the module into the mobile phone, these flexible boards 52 through 55 have to be bent. This bending process is extremely complicated, and so has a considerable influence on the productivity for the device. Also, due to a volume limitation against miniaturization as a whole, there is a problem that the mobile phone cannot be miniaturized satisfactorily.
Furthermore, since four flexible boards 52 through 55 are used, the materials cost becomes expensive. Additionally, since the flexible boards 52, 53, and 55 each have to be connected with the main flexible board 54 by means of solder joints 52b, 53b, and 55b, the numbers of assembling processes and components are large, which increases the manufacturing cost.